Electric shaver shear plate and method of manufacture



Patented Feb. 18, 1947 ELECTRIC SHAVER SHEAR PLATE AN METHOD OF MANUFACTURE Norman A. Gray, Stamford, Conn., assigner, by mesne assignments, to Schick Incorporated, a

corporation of Delaware Application November 3, 1944, Serial No. 561,683

(Cl. 'i6-104) 12 Claims. 1

This invention relates to electric shavers of the kind in which the shearing head, or so much of it as constitutes the shear-plate proper and its adjoining side walls, is formed up from a sheetmetal blank; and, While not limited thereto, it has particular application to shear-plates of this type provided with so-called combing, in the nature of overhanging edge portions serving to pick up and facilitate the entry of hair into the hairreceiving openings in the shear-plate.

The prima-ry object of the invention is a method of manufacture which results in a shear-plate combining maximum strength and shaving area While requiring a, minimum of machining operations for its production.

With the above and other objects in View, as Will hereinafter appear,v the invention comprises the methods, devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred and a modified embodiment of the invention, from which the severall features of the invention and the advantages attained thereby will be readily understood by those skilled in the. art.

In the drawing, Figs. 1 and 2 are sectioned perspectiveviews of a preferred form of the improved shearing head in dierent stages of manufacture, Fig. 3 is a sim-ilar View of a modified form, and Fig. 4 is a diagram illustrating certain of the forming operations incident to the manufacture of the shearing head.

In accordance with the presentinvention the shear-plate and its supporting walls are formed from a rectangular sheet metal blank pierced to provide suitable hair-receiving openings'. Such a blank, marked I, is indicated in section in Fig. 4. As there shown by the full-line outline, which represents the result of the first forming operation, the blank at this stage includes a central, curved portion 2', adjacent acute-angled portions 3 and recessed portions 4.

In the next forming operation the blank isl bent upto substantially U-shaped form andV given its ultimate general` contour, as illustrated in dotted outli-ne in Fig. 4.-. In this. operation the abovementioned central, curved portion has been bowedI outwardly toformtheshear-plate proper (genershear-plate portion of, the, U is embossed toA provide an outwardly projecting or raised panel. 6, Fig. 1, running throughout'.V the; length of thehead. The depth, or extent. of thev embossing is such that, the. inner surface 'I. of the embossed portion remains Within the contour of the outer surfaces The head is then mountedy onfa grinding arbor and the outer face of the shear-plate isground to an extent to reduce it to the smooth contour shown in Fig. 2'; that is, the raised portion of panel 6 is ground off, producing the uniformly thin, central shearing zone, marked II inyFig. 2, bordered by the thicker, supporting zones I2. If need be the grinding may, of course,vbe continued into thev zones I2 to the extent necessary to. reduce the central.. shearing zone I I to the thinness required, However, a limited portion I3 of panel ii, at each end of the head, is preferably l'efty intact, to provide a suitable reinforcement. Except'for nishing operations the head is then complete.

As above stated, the blank I fromA which the shear-plate and walls are formed is suitably.

pierced. In thi-s form, and preferably, the piercing takes the form of slots and so arranged as'to provide a central row of hair-receiving openings lli Wholy within the thin, central shearing zone.. On each side,y and staggered in relation to slots. I4. are slots I5 which extendl through the side walls 4. the combing 3 and into the thin, central zone. Thus a suitable inner cutter (not shown) bearing against and within the lateral limit-s' of the nether surface of the thin shearing zone can cooperate both withv the central slots I4. through. out their length, and withv the inner ends of the: slots I5.

Not only are the necessary machining operaitionsreduced to a minimum by the described method of manufacture, but also the resulting form of the shear-plate provides certain very denite advantages. The thickness of the side wals, providing maximum strength, continues.

through the combing and marginalshear-plate; zones clear up to the central or shaving zone;A and the latter, in turn, can be made uniformly extremely thin over a relatively wide area., Here,- tofore, as is well known, a common practice has'. been to grind the inner and outer surfaces of the shear-plate to taper the thickness outwardly from a thin central portion to thicker side portions,` achieving the necessary strength at the sides at the sacrifice of Width ofthe thin central' zone and intro.lucing intermediate zones of varying thickness greater than the minimum at' the centerl and' incapable of cutting as closely.

The shearing headl illustrated in Fig.- 3 differs from that shown. inFigs. 1 and2 only-in: the shapl of the shear-plate, which is fiat instead of curved. The method of manufacture isl the same.y The initial blank can be identical with that already described; and in the bending or second forming Y operation it is necessary only to change the central portion of the die to convert the central, curved portion 2 of the blank to nat rather than Y outwardly curved form. As in the Fig. 2 form,

the described embossing and grinding produces a thin, central, shearing zone I6 merging abruptly into thicker, marginal zones I '1.V The arrangement of the slots can also be the same as already described and the ends of the head reinforced,

as before, by refraining portions I8.

In the light of the foregoing description the. following is claimed:

1. A sheet metal shear-plate formed to provide a face-contacting zone having a smooth, convex, outer surface" and a stepped inner surface forming, with the outer surface, a thin lcentral porfrom grinding down the Y tion merging abruptly'into thicker marginal por- .Y formlythin central section abruptly merging into relatively` thick sections continuing into and through the combing portions.

3.*A sheet metal shear-plate having a smooth, convex; outer surface, a uniformly thin central zone merging abruptly'into uniformly thin but substantially thicker marginal zones, and hairreceivingopenings in the said central zone and in the said marginal zones.

'4. A shear-'plate havingv a smoothY convex outer 4 outer surfaces of the adjacent unembossed portions.

7. In the manufacture of electric shaver shearplates, the method which includes the forming of a pierced,rsheet metal blank into a substantially U-shaped member, and, coincidently, em-

' bossing a limited central portion only of the surface, vand an inner Vsurface spaced from the Y outer surface to provide a uniformlythin centralsection' abruptly merging into relatively thick marginal sections. A y n 5.- I n `the manufacture of electric shaver shearplates, the method which includes the steps of forming a'sheet metal blank into a substantially U- shaped member, embossing a limited central portion'only of the VU to project such portion outwardly to an extent such that the inner surface of theembossed portion remains within the contour of the outerrsurfaces 4of the adjacent unembossed portions, and grinding down the outwardly projected portion throughout at least part of its f Vlength to a depth to bring the outer surface thereof into conformity with the contour of the said outer surfacesof the adjacent unembossed por- Y tions and into parallelism with the said inner surface of the embossed portion, thereby producing a uniformly thin central portion merging into relatively thick marginal portions.

6. In the manufacture of electric shaver shear- Y plates, the methodwhich includes the steps of forming a sheet metal blankinto a substantially Y U-shaped member, embossing a limited Vcentral portion only of the U to project such portion outwardly to an extent such that the inner surface of the embossed portion remains within the contour ofthe outer surfaces of the adjacent unembossed portions, and grinding down the outwardly projected portion throughout at least part ofA its length to a depth to bring the outer surface thereofjinto conformity with the contour of the Said bridge portion of the U to provide outer marginal surfaces on each side of an abruptly Yraised surface.

8. A sheet metal shear-plate formed to provide a face-contacting zone bordered by converging walls forming acute-angled combing portions, the face-contacting zone having a smooth outer surface and a stepped inner surface forming, with the outer surface, a uniformly thin central portion merging abruptly into thicker marginal portions, spaced hair-receiving openings in theuniformly thin central portion, and hair-receiving slots, staggered with respect to said openings, ex-

tending through the combing portions and thicker marginal portions andY into the uniformly thin central portion.

9. A sheet metal shear-plate formed to provide a face-contacting zone bordered by converging walls forming acute-angled combing portions, the

face-contacting zone having a smooth outer surface and a stepped rinner surface forming, with the out-er surface, a uniformly thin central portion merging abruptly into thicker marginal portions, and hair-receiving slots, closed at their inner ends, extending throughrthe combing portions and thicker marginal portions and into the uniformly thin central portion.

10. A shear-plate having a smooth convex outer surface, and an inner'surface spaced from the outer surface to provide a uniformly thin central section abruptly merging into' relatively thick marginal sections, said shear-plate having hairreceiving slots extendingthrough the said marginal portions and into,v and terminating in the said uniformly thin central section.

11. A shear-plate having a smooth fiatV outer surface, and an inner surface spaced from the outer surface to provide-a uniformly thin central section abruptly merging into relatively thick marginal sections, said shear-plate having hairreceiving slots extending throughV the said marginal portions and into, and terminating in the said uniformly thin centralsection.

12. In the manufacture of electric shaver shearplates, the method whichincludes thesteps of forming a sheet metal blank into a substantially U-shaped member, embossing a limited central portion only of the bridge portion of the U to project such portion outwardly with respect to the contiguous surfaces of the balance of the bridge portion ofthe U, and grinding material off the outer surface of the embossed portion to produce a uniformly thin central portion merging abruptly into relatively thick marginal portions.

NORMAN A. GRAY.

REFERENCES CITED The following references are of record in the ille of this patent:V

UNITED STATES PATENTS Date Number Name 2,331,274 Martin Oct. 5, 1943 1,757,978 Schick May 13, 1930 2,220,166 Martin n Nov. 5, 1940 2,242,180 Jepson May 13, 1941 Law -u July21, 1942 

